Secondary synchronization codebook for E-UTRAN

ABSTRACT

Providing for secondary synchronization encoding utilizing a primary synchronization channel (P-SCH)-related scrambling code is described herein. Scrambled secondary synchronization codes (SSCs) can be assigned to multiple base stations of a radio access network (RAN). By way of example, PSC-based scrambling codes can be created from a plurality of M-sequences generated from a common polynomial expression. Further, an SSC codebook is provided that selects sequence pairs of a sequence matrix for generating SSCs. Selection can be based on transmission characteristics of resulting SSCs, providing reduced interference in planned, semi-planned and/or unplanned mobile deployments.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/996,636, titled “SECONDARY SYNCHRONIZATION CODEBOOK FOR E-UTRAN,”which is a continuation of U.S. patent application Ser. No. 13/214,602,titled “SECONDARY SYNCHRONIZATION CODEBOOK FOR E-UTRAN,” filed Aug. 22,2011, now U.S. Pat. No. 9,674,802, which is a divisional of U.S. patentapplication Ser. No. 12/166,495, titled “SECONDARY SYNCHRONIZATIONCODEBOOK FOR E-UTRAN,” filed Jul. 2, 2008, now U.S. Pat. No. 8,009,701,which claims priority to U.S. Provisional Patent Application No.60/955,623, titled “SECONDARY SYNCHRONIZATION CODEBOOK FOR E-UTRAN,”filed on Aug. 13, 2007, all of which are assigned to the assignee hereofand expressly incorporated by reference herein in their entirety.

BACKGROUND I. Field

The following relates generally to wireless communication, and morespecifically to determining a secondary synchronization codebook forselecting secondary synchronization codes for a radio network site.

II. Background

Wireless communication systems are widely deployed to provide varioustypes of communication content such as, e.g., voice content, datacontent, and so on. Typical wireless communication systems can bemultiple-access systems capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access systems can includecode division multiple access (CDMA) systems, time division multipleaccess (TDMA) systems, frequency division multiple access (FDMA)systems, orthogonal frequency division multiple access (OFDMA) systems,and the like.

Generally, wireless multiple-access communication systems cansimultaneously support communication for multiple mobile devices. Eachmobile device can communicate with one or more base stations viatransmissions on forward and reverse links. The forward link (ordownlink) refers to the communication link from base stations to mobiledevices, and the reverse link (or uplink) refers to the communicationlink from mobile devices to base stations. Further, communicationsbetween mobile devices and base stations can be established viasingle-input single-output (SISO) systems, multiple-input single-output(MISO) systems, multiple-input multiple-output (MIMO) systems, and soforth.

MIMO systems commonly employ multiple (N_(T)) transmit antennas andmultiple (N_(R)) receive antennas for data transmission. A MIMO channelformed by the N_(T) transmit and N_(R) receive antennas can bedecomposed into N_(S) independent channels, which can be referred to asspatial channels, where N_(S)≤{N_(T), N_(R)}. Each of the N_(S)independent channels corresponds to a dimension. Moreover, MIMO systemscan provide improved performance (e.g., increased spectral efficiency,higher throughput and/or greater reliability) if additionaldimensionalities created by the multiple transmit and receive antennasare utilized.

Improved performance, throughput and reliability provided bymulti-transmission wireless access sites can also introduce additionalsystem complexities. For instance, where multiple base stations aretransmitting within a common area, and such transmissions are receivedby a single device, a mechanism to distinguish between suchtransmissions can be required. Further, a means to distinguish and/oridentify one base station from another can be required. One mechanismfor identifying a base station(s) and distinguishing receivedtransmissions is by employing channel synchronization. Synchronizationcan include, in some instances, a primary synchronization code (PSC)that includes frequency and timing information for a transmission, and asecondary synchronization code (SSC) that provides base stationidentity. In such instances, a device can distinguish and decode one ormore transmissions in a multi-transmitter environment by way of the PSCand/or SSC.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

The subject disclosure, in at least some aspects, employs a primarysynchronization channel (P-SCH) related scrambling code to scramblesecondary synchronization codes (SSCs) of multiple base stations. Inaddition, various mechanisms are provided to accomplish the scrambling.In at least one additional aspect, PSC-based scrambling codes arecreated from a plurality of M-sequences generated from a polynomial thatis different from a polynomial utilized to generate an SSC. Furthermore,disclosed is an SSC codebook that selects sequence pairs to generateSSCs for multi-transmitter mobile sites based on power and/orcorrelation characteristics of the resulting scrambled SSCs. As aresult, interference between multi-transmitter SSC transmissionsreceived at a device can be mitigated, providing improved throughput,reliability and consistency for planned, semi-planned and unplannedmobile base station deployments.

According to some aspects, disclosed is a method for generating asecondary synchronization code (SSC) for wireless communication. Themethod can comprise generating a sequence matrix from a base M-sequenceand cyclic shifted variations of the base M-sequence and scrambling atleast one M-sequence of the sequence matrix with a common binaryscrambling code based on a primary synchronization code (PSC) associatedwith the wireless communication. Furthermore, the method can comprisegenerating an SSC from the at least one scrambled M-sequence and mappingthe SSC onto sub-carrier channels of an orthogonal frequency divisionmultiplex (OFDM) transmission.

According to other aspects, provided is an apparatus for generating anSSC for wireless communication. The apparatus can comprise a logicprocessor that generates a sequence matrix from a base M-sequence andcyclic shifted variations of the base M-sequence and a datatransformation module that scrambles at least one sequence of the matrixwith a common binary scrambling code based on a PSC associated with thewireless communication. In addition, the apparatus can comprise amultiplexing module that generates an SSC from the at least onescrambled sequence and a transmission processor that maps the SSC ontosub-carrier channels of an OFDM transmission.

According to still other aspects, disclosed is a further apparatus forgenerating an SSC for wireless communication. The apparatus can comprisemeans for generating a sequence matrix from a base M-sequence and cyclicshifted variations of the base M-sequence and means for scrambling atleast one sequence of the matrix with a common binary scrambling codebased on a PSC associated with the wireless communication. In addition,the apparatus can comprise means for generating an SSC from the at leastone scrambled sequence and means for mapping the SSC onto sub-carrierchannels of an OFDM transmission.

In additional aspects of the subject disclosure, provided is a processorconfigured to generate an SSC for wireless communication. The processorcan comprise a first module that generates a sequence matrix from a baseM-sequence and cyclic shifted variations of the base M-sequence and asecond module that scrambles at least one sequence of the matrix with acommon binary scrambling code based on a PSC associated with thewireless communication. The processor can further comprise a thirdmodule that generates an SSC from the at least one scrambled sequenceand a fourth module that maps the SSC onto sub-carrier channels of anOFDM transmission.

According to at least one further aspect, providing is acomputer-readable medium comprising computer-readable instructionsconfigured to generate an SSC for wireless communication. Theinstructions can be executable by at least one computer to generate asequence matrix from a base M-sequence and cyclic shifted variations ofthe base M-sequence and to scramble at least one sequence of the matrixwith a common binary scrambling code based on a PSC associated with thewireless communication. Furthermore, the instructions can be executableby at least one computer to generate an SSC from the at least onescrambled sequence and to map the SSC onto sub-carrier channels of anOFDM transmission.

According to some aspects, disclosed is a method of selecting distinctSSCs for a radio network site. The method can comprise forming asequence matrix from a base M-sequence and n cyclic shifted sequences ofthe base M-sequence and assigning one of substantially (n+1)^2 indicesto distinct sequence pairs of the sequence matrix. The method can alsocomprise selecting a sequence pair based at least in part on peak toaverage power ratio (PAPR) or signal correlation of an SSC resultingfrom the sequence pair.

In addition, according to other aspects, provided is an apparatus thatselects distinct SSCs for a radio network site. The apparatus cancomprise a logic processor that forms a sequence matrix from a baseM-sequence and n cyclic shifted sequences of the base M-sequence and anindexing module that assigns one of substantially (n+1)^2 indices todistinct sequence pairs of the sequence matrix. According to someaspect, the apparatus can also comprise a pruning module that selects asequence pair based at least in part on PAPR or signal correlation of anSSC resulting from the sequence pair.

In one or more additional aspects, disclosed is an apparatus thatselects distinct SSCs for a radio network site. The apparatus cancomprise means for forming a sequence matrix from a base M-sequence andn cyclic shifted sequences of the base M-sequence and means forassigning one of substantially (n+1)^2 indices to distinct sequencepairs of the sequence matrix. Furthermore, the apparatus can comprisemeans for selecting a sequence pair based at least in part on PAPR orsignal correlation of an SSC resulting from the sequence pair.

According to at least one other aspect, disclosed is a processorconfigured to select distinct SSCs for a radio network site. Theprocessor can comprise a first module that forms a sequence matrix froma base M-sequence and n cyclic shifted sequences of the base M-sequenceand a second module that assigns one of substantially (n+1)^2 indices todistinct sequence pairs of the sequence matrix. Additionally, theprocessor can comprise a third module that selects a sequence pair basedat least in part on PAPR or signal correlation of an SSC resulting fromthe sequence pair.

In addition to the foregoing, provided is a computer-readable mediumcomprising computer-readable instructions configured to select distinctSSCs for a radio network site. The instructions can be executable by atleast one computer to form a sequence matrix from a base M-sequence andn cyclic shifted sequences of the base M-sequence and to assign one ofsubstantially (n+1)^2 indices to distinct sequence pairs of the sequencematrix. Furthermore, the instructions can be executable by at least onecomputer to select a sequence pair based at least in part on PAPR orsignal correlation of an SSC resulting from the sequence pair.

According to additional aspects, disclosed is a method of wirelesscommunication. The method can comprise receiving wireless transmissionfrom a mobile network transmitter and extracting an SSC from thewireless transmission, the SSC is comprised of at least two sequencesscrambled with a common PSC-based binary scrambling code. The method canfurther comprise employing a common PSC-based binary descrambling codeto decipher the SSC and determining an identity of the mobile networktransmitter from the deciphered SSC.

In accordance with other aspects, provided is an apparatus forconducting wireless communication. The apparatus can include an antennathat receives wireless transmission from a mobile network transmitterand a demodulator that extracts an SSC from the wireless transmission,the SSC is comprised of at least two sequences scrambled with a commonPSC-based binary scrambling code. Furthermore, the apparatus can includea signal processor that employs a common PSC-based binary descramblingcode to decipher the SSC and a logic processor that determines anidentity of the mobile network transmitter from the deciphered SSC.

In accordance with still other aspects, disclosed is an apparatus thatconducts wireless communication. The apparatus can comprise means forreceiving wireless transmission from a mobile network transmitter andmeans for extracting an SSC from the wireless transmission, the SSC iscomprised of at least two sequences scrambled with a common PSC-basedbinary scrambling code. Further, the apparatus can comprise means foremploying a common PSC-based binary descrambling code to decipher theSSC and means for determining an identity of the mobile networktransmitter from the deciphered SSC.

In additional aspects, provided is a processor configured to conductwireless communication. The processor can comprise a first module thatreceives wireless transmission from a mobile network transmitter and asecond module that extracts an SSC from the wireless transmission, theSSC is comprised of at least two sequences scrambled with a commonPSC-based binary scrambling code. The processor can further comprise athird module that employs a common PSC-based binary descrambling code todecipher the SSC and a fourth module that determines an identity of themobile network transmitter from the deciphered SSC.

According to one or more further aspects, provided is acomputer-readable medium comprising computer-readable instructionsconfigured to conduct wireless communication. The instructions can beexecutable by at least one computer to receive wireless transmissionfrom a mobile network transmitter and to extract an SSC from thewireless transmission, the SSC is comprised of at least two sequencesscrambled with a common PSC-based binary scrambling code. Theinstructions can further be executable by at least one computer toemploy a common PSC-based binary descrambling code to decipher the SSCand to determine an identity of the mobile network transmitter from thedeciphered SSC.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe one or more aspects. These aspects are indicative, however, of but afew of the various ways in which the principles of various aspects canbe employed and the described aspects are intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a block diagram of an example system that provideswireless communication in accordance with aspects set forth herein.

FIG. 2 illustrates a block diagram of an example communication apparatusfor employment with a wireless communication environment.

FIG. 3 depicts a block diagram of an example system that providesreduced interference among SSCs of a multi-base station site accordingto one or more aspects.

FIG. 4 illustrates a diagram of an example sequence matrix forgenerating sequences for SSCs, scrambling codes, and/or the like.

FIG. 5 depicts a block diagram of an example system that providesreduced interference for transmitted SSCs in a multi-transmitter mobilesite.

FIG. 6 illustrates a block diagram of an example system that employs anSSC codebook described herein for reducing interference between SSCtransmissions.

FIG. 7 depicts a block diagram of an example base station according toaspects of the subject disclosure.

FIG. 8 illustrates a block diagram of an example terminal deviceaccording to still other aspects of the subject disclosure.

FIG. 9 depicts a flowchart of an example methodology for reducinginterference of multiple SSC transmissions according to aspects of thesubject disclosure.

FIG. 10 depicts a flowchart of a sample methodology for scrambling OTASSC transmission according to one or more aspects.

FIG. 11 illustrates a flowchart of a sample methodology for generatingscrambled SSCs according to at least one aspect.

FIG. 12 depicts a block diagram of an example system that can facilitateremote communication according to some aspects disclosed herein.

FIG. 13 depicts a block diagram of an example system that providesreduced interference for a mobile communication environment.

FIG. 14 depicts a block diagram of a sample system that selects SSCsequences based on PAPR and/or correlation of resulting SSC signals.

FIG. 15 illustrates a block diagram of a sample system that providesimproved reception and synchronization in a multi-transmitter mobileenvironment.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of one or more aspects. It can be evident, however, thatsuch aspect(s) can be practiced without these specific details. In otherinstances, well-known structures and devices are shown in block diagramform in order to facilitate describing one or more aspects.

In addition, various aspects of the disclosure are described below. Itshould be apparent that the teaching herein can be embodied in a widevariety of forms and that any specific structure and/or functiondisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereincan be implemented independently of any other aspects and that two ormore of these aspects can be combined in various ways. For example, anapparatus can be implemented and/or a method practiced using any numberof the aspects set forth herein. In addition, an apparatus can beimplemented and/or a method practiced using other structure and/orfunctionality in addition to or other than one or more of the aspectsset forth herein. As an example, many of the methods, devices, systemsand apparatuses described herein are descried in the context ofdetermining characteristics of one or more wireless channels andproviding a handover determination based in part on magnitudes of thedetermined characteristics. One skilled in the art should appreciatethat similar techniques could apply to other communication environments.

The subject disclosure provides, in one or more aspects, reducedinterference for multiple secondary synchronization code (SSC)transmission in a multi-transmitter environment. The environment can beassociated with a planned, semi-planned, and/or unplanned mobilecommunication environment. Typically, radio access network (RAN) basestations (BSs) employ synchronization codes to facilitate over the air(OTA) communication with mobile devices (e.g., cellular telephones,cellular-enabled laptops, multi-mode phones, personal digital assistants[PDAs], and/or the like). Mobile devices monitor the synchronizationcodes (and other portions of OTA transmissions in some instances) inorder to determine when pertinent data is being provided by a BS. Wheremany BSs exist within a relatively small communication site (e.g., suchthat a mobile device receives wireless transmission from many BSs), thesynchronization codes can interfere with each other, becoming difficultto distinguish at the mobile device. Accordingly, mechanisms to mitigateor avoid synchronization code interference can improve reliability ofmobile communications.

According to some aspects, particular mechanisms are provided togenerate and scramble an SSC with a P-SCH related scrambling code.Scrambled SSCs can be less likely to interfere with each other whentransmitted in a common mobile environment (e.g., a single mobiledeployment site, or multiple closely positioned mobile sites). In atleast one aspect, SSCs can be generated from a first set of sequencesprovided by a first mathematical expression, and scrambling codes toscramble the SSCs can be generated from a different mathematicalexpression. Further, sequence indexes of the scrambling codes can beselected based on a primary synchronization channel (P-SCH). Variousmechanisms can be employed to generate the scrambled SSCs and reduceinterference of multiple SSCs transmitted by multiple sources (e.g.,BSs).

SSCs can be generated from multiple sequences selected from a sequencematrix, comprising a base sequence and variations of the base sequence(e.g., cyclic shifted sequences). The base sequence, selected sequencesand/or SSC can be scrambled with a scrambling code(s) to reduceinterference of OTA SSCs. As one example, a pair of selected sequencescan first be scrambled by the scrambling code(s), the sequences can thenbe combined to form a full-length scrambled SSC sequence (e.g., byinterleaving the sequence pair), which can be mapped to an OTA message.In another example, the pair of sequences can first be interleaved toform an unscrambled full-length sequence and then scrambled by thescrambling code(s), then mapped to the transmission. In other examples,the base sequence can be scrambled such that the sequence matrixcomprises the scrambled base sequence and scrambled variations thereof.In such example, a pair of scrambled sequences can be selected from thematrix, interleaved to form a full-length SSC sequence, and mapped intothe OTA message. The scrambled SSC sequences can yield reducedinterference of transmitted SSCs and improve transmission reliabilityfor planned, semi-planned or unplanned mobile base station deployment.

According to one or more other aspects, a mechanism to generatePSC-based scrambling codes is provided that can randomize interferencebetween encoded signals. Multiple sequences (e.g., three sequences) areemployed to generate a scrambling code for one or more SSCs. Themultiple sequences can comprise a set of full-length sequences (or,e.g., modified full-length sequences, such as one-bit truncated), or aset of half-length sequences appended to other half-length sequences ofsuch a set. In at least one aspect, the set of full-length and/orhalf-length sequences are generated from a common M-sequence polynomial.In another aspect, the set of full-length and/or half-length sequencescan be generated from a plurality of M-sequence polynomials. In at leastone additional aspect, PSC-based scrambling codes are created from threehalf-length M-sequences generated from a polynomial that is differentfrom a polynomial utilized to generate an SSC.

In accordance with one or more other aspects, provided is an SSCcodebook for generating SSCs for a multi-transmitter mobile site. TheSSCs can be generated from various sequences of a sequence matrix. Thesequences can be selected based on PAPR and/or correlationdeterminations of SSCs that result from a pair of sequences. Thus, theresulting SSCs can exhibit improved transmission and reducedinterference because of such aspects of the subject disclosure.

As used in the subject disclosure, the terms “component,” “system,” andthe like are intended to refer to a computer-related entity, eitherhardware, software, software in execution, firmware, middle ware,microcode, and/or any combination thereof. For example, a component canbe, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program,and/or a computer. One or more components can reside within a processand/or thread of execution and a component can be localized on onecomputer and/or distributed between two or more computers. Further,these components can execute from various computer readable media havingvarious data structures stored thereon. The components can communicateby way of local and/or remote processes such as in accordance with asignal having one or more data packets (e.g., data from one componentinteracting with another component in a local system, distributedsystem, and/or across a network such as the Internet with other systemsby way of the signal). Additionally, components of systems describedherein can be rearranged and/or complemented by additional components inorder to facilitate achieving the various aspects, goals, advantages,etc., described with regard thereto, and are not limited to the preciseconfigurations set forth in a given figure, as will be appreciated byone skilled in the art.

Furthermore, various aspects are described herein in connection with amobile communication device (or, e.g., a mobile device). A mobilecommunication device can also be called a system, a subscriber unit, asubscriber station, mobile station, mobile, remote station, remoteterminal, access terminal, user terminal, user agent, a user device, oruser equipment. A subscriber station can be a cellular telephone, acordless telephone, a Session Initiation Protocol (SIP) phone, awireless local loop (WLL) station, a personal digital assistant (PDA), ahandheld device having wireless connection capability, or otherprocessing device connected to a wireless modem or similar mechanismfacilitating wireless communication with a processing device.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, middleware, microcode, orany suitable combination thereof. If implemented in software, thefunctions may be stored on or transmitted over as one or moreinstructions or code on a computer-readable medium. Computer-readablemedia includes both computer storage media and communication mediaincluding any medium that facilitates transfer of a computer programfrom one place to another. A storage media may be any available mediathat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code in the form of instructions or datastructures and that can be accessed by a computer. In addition, anyconnection is properly termed a computer-readable medium. For example,if the software is transmitted from a website, server, or other remotesource using a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

For a hardware implementation, the processing units various illustrativelogics, logical blocks, modules, and circuits described in connectionwith the aspects disclosed herein can be implemented or performed withinone or more application specific integrated circuits (ASICs), digitalsignal processors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), discrete gate or transistor logic, discrete hardwarecomponents, general purpose processors, controllers, micro-controllers,microprocessors, other electronic units designed to perform thefunctions described herein, or a combination thereof. A general-purposeprocessor can be a microprocessor, but, in the alternative, theprocessor can be any conventional processor, controller,microcontroller, or state machine. A processor can also be implementedas a combination of computing devices, e.g., a combination of a DSP anda microprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suitableconfiguration. Additionally, at least one processor can comprise one ormore modules operable to perform one or more of the steps and/or actionsdescribed herein.

Moreover, various aspects or features described herein can beimplemented as a method, apparatus, or article of manufacture usingstandard programming and/or engineering techniques. Further, the stepsand/or actions of a method or algorithm described in connection with theaspects disclosed herein can be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.Additionally, in some aspects, the steps and/or actions of a method oralgorithm can reside as at least one or any combination or set of codesand/or instructions on a machine-readable medium and/or computerreadable medium, which can be incorporated into a computer programproduct. The term “article of manufacture” as used herein is intended toencompass a computer program accessible from any computer-readabledevice, carrier, or media. For example, computer-readable media caninclude but are not limited to magnetic storage devices (e.g., harddisk, floppy disk, magnetic strips . . . ), optical disks (e.g., compactdisk (CD), digital versatile disk (DVD) . . . ), smart cards, and flashmemory devices (e.g., card, stick, key drive . . . ). Additionally,various storage media described herein can represent one or more devicesand/or other machine-readable media for storing information. The term“machine-readable medium” can include, without being limited to,wireless channels and various other media capable of storing,containing, and/or carrying instruction(s) and/or data.

Additionally, the word “exemplary” is used herein to mean serving as anexample, instance, or illustration. Any aspect or design describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs. Rather, use of the wordexemplary is intended to present concepts in a concrete fashion. As usedin this application, the term “or” is intended to mean an inclusive “or”rather than an exclusive “or”. That is, unless specified otherwise, orclear from context, “X employs A or B” is intended to mean any of thenatural inclusive permutations. That is, if X employs A; X employs B; orX employs both A and B, then “X employs A or B” is satisfied under anyof the foregoing instances. In addition, the articles “a” and “an” asused in this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

As used herein, the terms to “infer” or “inference” refer generally tothe process of reasoning about or inferring states of the system,environment, and/or user from a set of observations as captured viaevents and/or data. Inference can be employed to identify a specificcontext or action, or can generate a probability distribution overstates, for example. The inference can be probabilistic-that is, thecomputation of a probability distribution over states of interest basedon a consideration of data and events. Inference can also refer totechniques employed for composing higher-level events from a set ofevents and/or data. Such inference results in the construction of newevents or actions from a set of observed events and/or stored eventdata, whether or not the events are correlated in close temporalproximity, and whether the events and data come from one or severalevent and data sources.

Referring now to the drawings, FIG. 1 illustrates a wirelesscommunication system 100 with multiple base stations 110 and multipleterminals 120, such as can be utilized in conjunction with one or moreaspects. A base station (110) is generally a fixed station thatcommunicates with the terminals and can also be called an access point,a Node B, or some other terminology. Each base station 110 providescommunication coverage for a particular geographic area or coveragearea, illustrated as three geographic areas in FIG. 1, labeled 102 a,102 b, and 102 c. The term “cell” can refer to a base station and/or itscoverage area depending on the context in which the term is used. Toimprove system capacity, a base station geographic area/coverage areacan be partitioned into multiple smaller areas (e.g., three smallerareas, according to cell 102 a in FIG. 1), 104 a, 104 b, and 104 c. Eachsmaller area (104 a, 104 b, 104 c) can be served by a respective basetransceiver subsystem (BTS). The term “sector” can refer to a BTS and/orits coverage area depending on the context in which the term is used.For a sectorized cell, the BTSs for all sectors of that cell aretypically co-located within the base station for the cell. Thetransmission techniques described herein can be used for a system withsectorized cells as well as a system with un-sectorized cells. Forsimplicity, in the following description, unless specified otherwise,the term “base station” is used generically for a fixed station thatserves a sector as well as a fixed station that serves a cell.

Terminals 120 are typically dispersed throughout the system, and eachterminal can be fixed or mobile. A terminal can also be called a mobilestation, user equipment, a user device, or some other terminology. Aterminal can be a wireless device, a cellular phone, a personal digitalassistant (PDA), a wireless modem card, and so on. Each terminal 120 cancommunicate with zero, one, or multiple base stations on the downlinkand uplink at any given moment. The downlink (or forward link) refers tothe communication link from the base stations to the terminals, and theuplink (or reverse link) refers to the communication link from theterminals to the base stations.

For a centralized architecture, a system controller 130 couples to basestations 110 and provides coordination and control for base stations110. For a distributed architecture, base stations 110 can communicatewith one another as needed. Data transmission on the forward link oftenoccurs from one access point to one access terminal at or near themaximum data rate that can be supported by the forward link and/or thecommunication system. Additional channels of the forward link (e.g.,control channel) can be transmitted from multiple access points to oneaccess terminal. Reverse link data communication can occur from oneaccess terminal to one or more access points.

FIG. 2 is an illustration of an ad hoc or unplanned/semi-plannedwireless communication environment 200, in accordance with variousaspects. System 200 can comprise one or more base stations 202 in one ormore cells and/or sectors that receive, transmit, repeat, etc., wirelesscommunication signals to each other and/or to one or more mobile devices204. As illustrated, each base station 202 can provide communicationcoverage for a particular geographic area, illustrated as fourgeographic areas, labeled 206 a, 206 b, 206 c and 206 d. Each basestation 202 can comprise a transmitter chain and a receiver chain, eachof which can in turn comprise a plurality of components associated withsignal transmission and reception (e.g., processors, modulators,multiplexers, demodulators, demultiplexers, antennas, and so forth.), aswill be appreciated by one skilled in the art. Mobile devices 204 canbe, for example, cellular phones, smart phones, laptops, handheldcommunication devices, handheld computing devices, satellite radios,global positioning systems, PDAs, and/or any other suitable device forcommunicating over wireless network 200. System 200 can be employed inconjunction with various aspects described herein in order to facilitateproviding and/or utilizing synchronized OTA message transmission in awireless communication environment (200), as set forth herein withregard to subsequent figures.

FIG. 3 is a block diagram of an example system 300 that provides reducedinterference for synchronization messages in a mobile communicationenvironment. A synchronization message as utilized in the context ofsystem 300 can include an SSC. It should also be appreciated thataspects of a primary synchronization code (PSC), or of a P-SCH, can beemployed to reduce interference of an SSC, as discussed herein. Itshould be further appreciated that a mobile communication environmentpertinent to system 300 can include a third generation partnershipproject (3GPP) long term evolution (LTE), referred hereinaftercollectively as LTE, system, an evolved universal mobiletelecommunication system (UMTS) terrestrial radio access network(E-UTRAN) system, or a combination thereof or of the like. For instance,other suitable mobile communication architectures employing orthogonalfrequency division multiple access (OFDMA) access technology, frequencydivision multiplexing (FDM), including e.g., orthogonal FDM (OFDM),coded OFDM (COFDM), and/or the like, are included in such a mobilecommunication environment. It should further be appreciated that one ofskill in the art may determine appropriate mechanisms to apply the belowtechniques to other mobile communication environments, including codedivision multiple access (CDMA) environments (e.g., CDMA2000, 3GPP2,etc.), time division multiple access (TDMA) environments (e.g., TDMA),time division duplex (TDD) environments, or suitable combinationsthereof (e.g., TD-CDMA, TD-SCDMA, UMTS-TDD, FDMA/TDMA/FDD, etc.).

System 300 can comprise an SSC generator 302 coupled to one or more basestations of a RAN 306 (e.g., an E-UTRAN). One or more devices 304 can beserviced by the RAN 306. The base stations (306) can communicate withthe mobile device 304 by exchanging OTA messages there with. An OTAmessage sent to the mobile device(s) 304 typically include one or moresynchronization messages to facilitate such communication. For instance,a PSC can be utilized to indicate where data is packed in the message,message length, synchronization frequency, or the like. An SSC canprovide the prior information, as well as an identity of a transmittingbase station 306. Thus, the SSC can be utilized by the mobile device 304to distinguish one base station (306) from another (306) in amulti-transmitter site 306.

Where multiple OTA messages are transmitted by multiple base stations,at substantially concurrent times, interference between the messages canresult. Interference with respect to synchronization information canlead to missed messages, increased power consumption at mobile device304, and communication inefficiency. To mitigate occurrence ofinterference, SSC generator 302 can employ one or more scrambling codesto reduce likelihood that two SSCs will interfere with each other at areceiving device (304).

System 300 can further comprise a logic processor 308 that generates asequence matrix utilized to create one or more SSCs for base stations ofthe RAN 306. For instance, a sequence, sequence pair, sequence triplet,etc., can be utilized to generate an SSC. In one aspect, pairs oflength-31 sequences (e.g., binary sequences having 31 binary bits) areemployed to generate 62 bit SSCs. The sequence pairs can be selectedfrom the sequence matrix generated by logic processor 308. In oneexample, the sequence matrix can be generated from a single baseM-sequence of length-31. Such a sequence can be derived from a suitablepolynomial expression. In other aspects, logic processor 308 derives thebase M-sequence from a different polynomial expression than that used bya data transformation module 310 (below) to generate sequences for SSCscrambling codes. As a particular example, the polynomial expressionutilized to generate the base M-sequence can be of the form x^5+x^2+1over GF(2), where GF(2) indicates a Galois Field that limits results ofthe expression to binary digits.

Once a base sequence is generated by the logic processor 308, variationsof the base sequence can be formed to populate the sequence matrix. Insome aspects, a number of variations are generated that is substantiallyequivalent to a number of digits of the base sequence. (E.g., if thebase sequence comprises 31 digits, 29, 30, 31, or substantially similarnumber of variations are generated). The variations are combined withthe base sequence to form the sequence matrix (e.g., where the first,second, third, etc., rows of the matrix comprise the base sequence,first variation, second variation, etc., respectively, and where thefirst, second, third, etc., columns of the matrix comprise the first,second, third, etc., digits of each sequence, respectively—e.g., seeFIG. 4, supra).

Once the sequence matrix is defined, logic processor can select multiplesequences from the matrix that can be utilized to generate an SSC. Asone example, a pair of length-31 sequences can be selected to form alength-62 SSC. Each such SSC can then be assigned to one or more basestations of the RAN 306, and can carry identifying information (e.g.,base station ID) distinguishing such base stations from other basestations. As discussed in more detail at FIGS. 5 and 6, infra, theselection can be based on multiple factors, including, but not limitedto, PAPR of a resulting SSC, or signal correlation, or a combinationthereof or of the like. To reduce interference between SSCs transmittedby RAN 306, the SSCs can be scrambled by employing one or morescrambling sequences, such as a PSC-bases sequence, discussed below.

System 300 can further comprise a data transformation module 310 thatscrambles at least one sequence of a sequence matrix with a commonbinary scrambling code. In at least one aspect, the scrambling code canbe generated by a sequence module 312 that employs sequences derivedfrom a common polynomial expression. The common polynomial expressionand/or derived sequences can be based on a PSC associated with wirelesscommunication (e.g., OTA message). As an example, indices derived fromthe PSC can be employed to select sequence pairs, sequence triplets, orthe like (e.g., from a scrambling code sequence matrix), to generate thescrambling code. Selection of scrambling code sequences based on the PSCcan provide reduced interference for OTA transmission of multiple SSCs.

It should be appreciated that the data transformation module 310 canemploy the scrambling sequence to scramble a multiplexed SSC, componentsof an SSC (e.g., sequences of a sequence pair, triplet, etc., that formthe SSC), or sequences of the sequence matrix itself. In one particularexample, data transformation module 310 can scramble a base sequenceutilized to generate a sequence matrix. Derivative sequences of thescrambled base sequence (e.g., cyclic shifted variations) utilized toform the sequence matrix are inherently scrambled as well. Accordingly,a sequence matrix can be formed of scrambled sequences (e.g., byemploying the scrambled base sequence or variations thereof),unscrambled sequences (e.g., by employing the unscrambled base sequenceand variations thereof), or both. A matrix of scrambled sequences can beselected by logic processor 308, interleaved by multiplexing module 314,and mapped to an OTA message by transmission processor 316, as discussedin more detail below.

In other examples, a scrambling code can be applied to one or morenon-scrambled sequences selected from an unscrambled sequence matrix.For instance, data transformation module 310 can scramble multiple shortsequences selected from such a matrix that are then interleaved by amultiplexing module 314 to form a full-length SSC sequence. As anotherexample, multiplexing module 314 can interleave the short sequencesfirst, and then provide the resulting full-length sequence to the datatransformation module 310, which scrambles the full-length sequence. Thescrambled sequence is then utilized as an SSC for one or more basestations (306).

Various types of scrambling codes, as known in the art or made known toone of skill in the art by way of the context provided herein, can begenerated by sequence module 312. As mentioned above, sequence module312 can generate various sequences (e.g., M-sequences) from a commonpolynomial expression, or different polynomial expressions. In at leastone aspect, three length-63 M-sequence based scrambling codes aregenerated, where each length-63 sequence is truncated by one bit to forma scrambling code (or, e.g., one bit is changed to 0 and mapped to a DCtone of a wireless transmission). In another example, three length-31M-sequence based scrambling codes are generated, and repetition isemployed to generate three length-62 scrambling codes (e.g., where B isa length-31 sequence, repetition can be of the form [B, B]).

In at least one particular aspect, each of multiple scrambling codesequences can be formed from a single polynomial expression. In oneaspect, the polynomial expression can be of the form 1+x^2+x^3+x^4+x^5.A resulting scrambling code sequence can be represented by C(0,n). As aspecific example of a suitable scrambling sequence, C(0,n) can denotethe following M-sequence:

C(0,n)={−1,1,1,1,−1,−1,−1,1,−1,1,−1,1,1,−1,1,−1,−1,−1,−1,1,1,−1,−1,1,−1,−1,1,1,1,1,1}

The above sequence C(0,n) can represent a base M-sequence. Cyclicshifted variations of the base M-sequence (e.g., see FIG. 4, infra) canbe defined as C(k,n)=C(0,(n+k) mod N). Accordingly, length-63 scramblingcodes can be obtained as:

[C(u,0),C(u,0), . . . ,C(u,14),C(u,14),C(u,15),0,C(u,15),C(u,16),C(u,16), . . . ,C(u,30),C(u,30)]

where 0 can be mapped to a DC tone of a frequency-based transmission. Itshould be appreciated that other length codes can be generated bysetting suitable values for k and n for C(k,n) (e.g., k and n can havesuitable values greater than 0). For the length-63 case, distinctscrambling codes can be generated by selecting distinct values of ‘u’.Values of ‘u’ can be selected based on a desired number of scramblingcode sequences for a set of such sequences. For instance, five, ten,twenty, etc., variations of the base M-sequence can be selected. For 31possible sequences, ‘u’ can correspond to the set {0, . . . , 30}.

In at least one aspect, sequence module 312 can generate threescrambling sequences from the formula C(k,n)=C(0,(n+k) mod N). Thescrambling codes can correspond to the following three values of ‘u’:{0, 10, 20}, thus utilizing the base M-sequence, a tenth cyclic shiftedvariation of the base sequence, and a twentieth cyclic shifted variationof the base sequence. The resulting three scrambling code sequences are:

C(0,n)={−1,1,1,1,−1,−1,−1,1,−1,1,−1,1,1,−1,1,−1,−1,−1,−1,1,1,−1,−1,1,−1,−1,1,1,1,1,1}

C(10,n)={−1,1,1,−1,1,−1,−1,−1,−1,1,1,−1,−1,1,−1,−1,1,1,1,1,1,−1,1,1,1,−1,−1,−1,1,−1,1}

C(20,n)={1,−1,−1,1,−1,−1,1,1,1,1,1,−1,1,1,1,−1,−1,−1,1,−1,1,−1,1,1,−1,1,−1,−1,−1,−1,1}

The foregoing scrambling sequences can be employed to generatescrambling codes of varying length (e.g., length-62 scrambling code) andcombined with SSC sequences. Scrambled sequences are mapped intowireless transmissions, as discussed below. By employing scramblingsequences of a common polynomial expression, a significant reduction ininterference among transmitted SSCs can be accomplished

System 300 can further comprise a transmission processor 316. Thetransmission processor 316 can map an SSC onto components of an OTAmessage. Specifically, the SSC can be mapped onto sub-carrier channelsof a frequency based message (e.g., FDM, OFDM, OFDMA), onto codedivisions of a code based message (e.g., CDMA, CDMA-2000, wideband CDMA[WCDMA]), onto time divisions of a time based message (e.g., TDMA), orsuitable sub-components of combined system messages (e.g., TD-CDMA,TD-SCDMA, UMTS-TDD, FDMA/TDMA/FDD, etc.). The OTA message can bereceived at mobile device 304, which can employ suitable techniques fordecoding the message and the SSC. In at least one instance, the mobiledevice 304 can employ a substantially inverse process for decoding theSSC as SSC generator 302 employs for coding/scrambling the SSC.Instructions for decoding the SSC can be pre-loaded onto the mobiledevice 304, downloaded from a network patch or the like (e.g., asoftware and/or firmware patch at a service provider's network server),or included within the OTA message (e.g., in a message preamble, or thelike).

As described, system 300 can provide substantial benefit for wirelesscommunications. SSC scrambling codes generated from a common polynomialexpression and indexed based on a corresponding PSC can result inreduced interference for SSCs transmitted by multiple base stations(306). Such a result can be of even greater benefit where large numbersof base stations (306) exist in a semi-planned or un-planned deployment,where interference can be high and signal to noise ratios (SNR)relatively low. Accordingly, system 300 can provide for increasedefficiency and OTA reliability even for unfavorable wirelessenvironments.

FIG. 4 illustrates an example sequence matrix 400 that can be utilizedto generate synchronization codes and/or scrambling codes for variousaspects described herein. Sequence matrix 400 comprises a number ofsequences represented by rows of the matrix 400. The first (top) row ofthe matrix is a base sequence. Lower rows of the matrix are variationsof the base sequence. As depicted in FIG. 4, the lower rows are cyclicshifted variations of the base sequence, although it should beappreciated that other suitable variations of a binary base sequence,known in the art, can be utilized to generate a similar sequence matrixto that depicted at 400. As depicted by the arrows in shown amongst thesequence matrix 400, the cyclic shift is a single digit shift wherebyvariations of the base sequence are formed by shifting each sequence bitone position, or one matrix column, as compared to a previous sequence.Thus, bit 1 for the base sequence is −1, and a first cyclic shiftedvariation of the base sequence, depicted at row 2 of the matrix, has thesame −1 in the second bit (second column). Further, each bit of the basesequence is shifted into the next right-most column in the first cyclicshifted sequence. It should be appreciated that multiple cyclic shiftscan be employed instead, such that each bit is shifted two columns,three columns, etc., with respect to previous sequences instead of asingle column.

Additional rows of the matrix exhibit further shifts of the basesequence. Thus, bits of the second cyclic shifted sequence (row 3) areshifted two columns from the base sequence (row 1), and so on,throughout each row. For a matrix having ‘L’ columns, based on sequencelengths of ‘L’, the matrix can comprise at least ‘L’ unique sequences,including the base sequence and L-1 single cyclic shifted variations ofthe base sequence. Such a sequence can be employed to generatesynchronization codes and/or scrambling codes as described herein. Where‘L’ matches a desired code length, single sequences of the matrix 400can be employed to create such codes. Alternatively, where ‘L’ isshorter than the desired code length, multiple sequences of the matrix400 can be employed to create the code(s).

As an example to illustrate the foregoing, a desired code length (e.g.,SSC length) is 62 bits. Where ‘L’ is equal to 62, a single sequence ofthe matrix 400 can be utilized to form a code. Where ‘L’ is equal to 31,sequence pairs of the matrix 400 can be interleaved to from the code.Where ‘L’ is equal to 21, a sequence triplet, with one of the sequencestruncated by one bit, can be interleaved to generate the code. It shouldalso be appreciated that substantially similar sequence lengths can beemployed in conjunction with bit truncation and/or bit repetition (e.g.,a length-63 M-sequence can be truncated by one bit to form the length-62code, also length-30 or length-32 sequence pairs can be employed inconjunction with single bit repetition or truncation, respectively, toform the length-62 code, etc.).

For dense base station deployment, where dozens or hundreds of basestations operate at a common geographic site (e.g., see FIG. 1, supra),employing pairs, triplets, etc., of sequences of shorter length than atarget code length can be beneficial. This is due to the fact that manymore unique sequence pairs, triplets, etc., can be extracted from thesequence matrix 400 than single sequences. For instance, if ‘L’ is equalto 62, and a desired SSC length is 62 bits, 62 unique single sequencesexist to form 62 distinct SSCs. However, where matrix 400 has ‘L’=31,and for a length-62 SSC, there are 961 (31^2) sequence pairs that canform 961 different SSCs. As another example, for ‘L=20’ or ‘L=21’(employing bit repetition or truncation) there are 8,000 or 9261,respectively, sequence triplet combinations that can generate differentSSCs. Accordingly, by selecting an appropriate sequence length withrespect to a desired SSC length, and employing pairs, triplets, etc., ofsequences, a number of unique codes generated by a matrix (400) can beincreased.

In at least one specific example of the claimed subject matter, matrix400 is a square matrix having 31 M-sequences of length ‘L’ equal to 31.The base sequence is a binary sequence generated from a polynomialexpression of the form x^5+x^2+1 over GF(2). Further, the additionalsequences are single cyclic shifted variations of the base sequence(e.g., as depicted by the arrows of the sequence matrix 400). Pairs ofsequences can be selected and interleaved to form various distinct SSCcodes. As described elsewhere herein, SSC scrambling can be implementedin various ways (e.g., see FIG. 3, supra). In one example, the selectedpairs can be interleaved to form length-62 sequences and then scrambled.Alternatively, the selected length-31 sequences can be scrambled andthen interleaved to form the length-62 sequence. As yet anotheralternative, the base M-sequence can be scrambled, such that each cyclicshifted variation of the matrix 400 is also scrambled. Scrambledsequence pairs can then be selected and interleaved to form thelength-62 SSC code. Optionally, a 0 bit can be added to the length-62codes to form length-63 codes, where the 0 bit is mapped to a DC tone ofa wireless transmission. Thus, a variety of mechanisms can be employedto reduce interference of overlapping wireless messages received at adevice, providing improved reception and overall communication, as wellas potentially reducing power at the receiving device (e.g., by avoidingrepeat transmission).

FIG. 5 depicts a block diagram of an example system 500 that providesreduced interference for transmitted SSCs in a multi-transmitter mobilesite. More specifically, system 500 provides a selective codebook forchoosing sequence combinations for generating resulting SSCs. In someaspects, the sequence combinations can be based on underlyingcharacteristics of a resulting SSC. Accordingly, improved wirelesstransmission can be accomplished by properly selecting SSCs that yielddesirable traits in a mobile communication environment.

System 500 includes an SSC index selector 502 that identifies a sequenceor group of sequences (e.g., sequence pair) for generating one or moreSSCs that can be assigned to a base station 504 of a RAN (not depicted,but see FIG. 3, at 306). The SSC index selector 502 can comprise a logicprocessor 506 that forms a sequence matrix from which the sequence orgroup of sequences can be selected. The sequence matrix can be formedutilizing a base sequence and a number of variations of the basesequence. In at least one aspect, the base sequence is a binaryM-sequence of length n+1, and the matrix comprises the base sequence andn cyclic shifted variations of the base sequence (e.g., as depicted atFIG. 4, supra). An indexing module 508 can assign indices to sequencesand/or groups of sequences of the sequence matrix. Sequences/groups ofsequences can be selected by reference to an assigned index. In at leastone aspect of the subject disclosure, the index module assignssubstantially (n+1)^(x) indices, where x is a number of sequences in agroup. Thus, for single sequences, substantially n+1 indices areassigned. For sequence pairs, substantially (n+1)^2 indices areassigned, and so on.

Where more distinct SSC sequence combinations exist than base stations(504) requiring an SSC, a pruning module 510 can selectsequences/sequence groups based on characteristics of a resulting SSC.The characteristics can be based on results of a signal emulator, forinstance, that can determine interference, power loss,cross-correlation, and like characteristics of an SSC.Sequences/sequence groups yielding SSCs with desirable characteristics,such as low PAPR, can be selected to generate SSCs.

As a particular example to illustrate aspects of system 500, logicprocessor 506 defines a sequence matrix having 31 length-31 sequences.Sequence pairs of the matrix can be represented by (u, v), where u and vboth have values {0, . . . , 30}. A number of length-62 SSCs can begenerated based on the sequence pairs (u,v) of the sequence matrix.Indexing module 508 assigns (n+1)^2, or 961, indices to the 961 distinctsequence pairs of the sequence matrix. An algorithm of the form r=u*31+vcan be used to generate these indices. In one aspect of the example,pruning module 510 selects 170 of the 961 distinct indices based oncharacteristics of SSC signals comprised of the sequence pairs (e.g.,including scrambling, such as provided by a common PSC-based scramblingcode, and interleaving the sequences). One or more of the selected SSCs(e.g., a pair), can then be modulated by a transmission processor 512(e.g., employing a modulator, signal coder, etc.) into a radio frame toresolve a frame boundary of the radio frame. As one particular aspect ofthe example, the following SSC indices r=u*31+v corresponding to amaximum PAPR of substantially 6.75 decibels (dB) can be employed:

16 18 20 33 62 63 66 70 71 75 80 83 93 99 104 105 113 116 121 125 126140 153 168 169 170 173 189 190 191 203 204 210 211 220 226 228 233 236241 251 261 267 268 270 278 287 293 300 304 313 317 327 332 336 338 339344 346 355 367 377 379 388 395 399 401 417 418 419 422 424 426 435 439445 452 453 456 457 466 475 478 482 486 488 493 498 508 515 516 517 518531 533 534 543 546 553 554 560 565 587 589 592 606 614 618 621 623 625628 631 636 645 653 665 677 678 684 700 707 708 711 713 714 719 725 728735 738 745 751 752 755 765 770 777 781 789 797 801 802 810 816 818 819826 829 831 851 854 856 862 863 871 879 889 897 901 909 910 913 916 917930 938 940 946 954

In another aspect of the example, pruning module 510 selects 340 of the961 distinct indices, also based on characteristics of SSC signalscomprised of the selected sequence pairs. Different tones derived fromone or more of 340 resulting SSCs (e.g., different tones of a pair ofSSCs) can be modulated by transmission processor 512 into the radioframe to resolve the frame boundary of the radio frame. In one specificaspect, the following SSC indices r=u*31+v can be employed thatcorrespond to a maximum PAPR of substantially 7.18 dB:

2 5 6 7 11 14 17 18 20 23 27 30 33 37 39 41 43 44 47 50 53 60 61 63 6566 68 70 71 74 75 80 84 86 88 99 101 102 104 105 107 111 113 114 115 116121 125 126 137 140 144 151 153 155 158 168 169 170 173 183 187 189 190191 197 203 204 205 209 210 211 212 217 219 220 225 226 227 228 233 236238 240 241 257 259 261 263 266 267 268 270 271 276 277 278 285 286 290292 293 294 300 303 304 306 307 310 311 312 313 316 317 327 331 332 336338 339 341 342 344 346 347 353 359 360 362 363 365 372 373 374 377 379382 383 388 394 399 401 406 413 417 418 419 420 421 422 424 426 430 439442 445 446 450 452 453 454 456 457 463 466 475 478 482 483 485 486 492493 494 495 498 499 505 506 508 513 515 516 517 518 519 527 528 531 533534 539 543 549 550 553 554 560 565 569 570 571 572 573 579 583 587 588589 590 592 594 596 603 606 607 609 610 614 620 621 625 630 631 634 636637 642 645 646 653 657 659 661 664 668 675 677 678 679 681 682 684 686690 694 699 700 702 707 708 709 720 725 726 728 732 733 735 738 739 740741 747 751 752 753 755 760 764 767 770 772 773 780 781 782 785 787 789791 795 797 801 802 805 810 811 815 818 819 821 823 825 826 830 831 838842 845 846 851 853 854 856 862 863 868 871 875 876 878 879 881 889 891892 897 901 906 907 909 910 913 916 917 918 919 925 930 935 936 940 942943 944 951 954 957 959

In yet another example for selecting code indices, 170, 340, or anothersuitable number of indices can be selected based on minimizing a numberof overlapping code indices used in a single SSC. For example, a firstset of length-31 sequences ‘u’ can employ indices {0, 1, 2, . . . , 19}.A second set of length-31 sequences ‘v’ can employ indices {11, 13, 14,. . . , 30} such that overlap between ‘u’ and ‘v’ sequences of resultingSSCs are minimized. Reduced index overlap can, in some instances,provide reduced interference between transmitted codes.

As described, system 500 can provide an SSC codebook that selects SSCsbased on underlying characteristics of the transmitted synchronizationsignal. Such a result can lead to improved signal reception for terminaldevices in a mobile environment, a decrease in repetitive traffic (e.g.,fewer data retransmission requests), and lower power consumption forsuch terminals. Accordingly, substantial benefits can be provided bysystem 500 for a mobile communication environment.

FIG. 6 illustrates a block diagram of an example system 600 that employsan SSC codebook as described herein for reducing interference betweenSSC transmissions. Selection of SSC codes can be based on comparison oftransmission power and/or cross-correlation characteristics of asimulated SSC and one or more thresholds. Resulting SSC(s) can bemodulated into a wireless transmission (e.g., a radio frame) to resolvea frame boundary of the transmission. Because SSC selection is based onunderlying SSC characteristics, improved power and/or correlationcharacteristics can be provided by system 600 for mobile communications.

System 600 comprises an SSC index selector 602 that indexes sequences orgroups of sequences of a sequence matrix. The index selector can selectone or more indices based on power and/or cross-correlationcharacteristics of a simulated SSC code 604 that results from aparticular sequence(s) identified by an index. Determined power and/orcross-correlation characteristics can be qualified based on comparisonto one or more thresholds. For instance, pruning module 606 cancondition selection of a particular index based on comparison of SSCPAPR to a PAPR threshold (e.g., based on a nominal OFDM symbol),comparison of SSC cross-correlation to a cross-correlation threshold, orboth. Thus, resulting SSCs can be generated that have predeterminedquality characteristics.

System 600 can employ a signal simulation module 608 to determine PAPRof simulated SSCs (604) resulting from a sequence(s) identified by aparticular index. Signal simulation module 608 can compare thedetermined PAPR to a threshold PAPR, and forward the results to pruningmodule 606. A relatively low PAPR is typically beneficial (e.g., ascompared with transmission of typical frequency-modulated signals) forwireless transmission, resulting in negligible impact on downlinktransmissions in many instances. Thus, the threshold can typicallyspecify some maximum acceptable PAPR, an acceptable range within adesired PAPR (e.g., within 3 dB of the desired PAPR), a number of SSCsbelow the desired PAPR (e.g., 30 SSCs having PAPR values below thedesired PAPR), or the like, or a suitable combination thereof.

System 600 can also employ a signal correlation module 610 thatdetermines a cross-correlation factor of simulated SSCs (604) resultingfrom a sequence(s) identified by a particular index. Signal correlationmodule 610 can compare a determined cross-correlation to across-correlation threshold to qualify the simulated SSC 604. Signalsstrongly correlated with other signals can often exhibit highinterference, thus minimal cross-correlation can be desired.Accordingly, pruning module 606 can condition selection of a particularsequence index based at least in part on cross-correlation being equalor lower than the threshold correlation. In some aspects, pruning module606 can condition selection of a particular sequence index on acombination of PAPR results and cross-correlation results. For instance,if a simulated SSC (604) has a PAPR lower than a threshold PAPR andcorrelation lower than a correlation threshold, an index associated withthe simulated SSC (604) can be selected. As described, system 600provides a convenient mechanism for selecting indices of a sequencematrix in order to provide beneficial PAPR and/or low cross-correlationcharacteristics, resulting in improved wireless transmission andreliability in many instances.

FIG. 7 depicts a block diagram of an example system 700 comprising abase station 702 and one or more mobile devices 704 according to aspectsof the subject disclosure. In at least one aspect of the subjectdisclosure, base station 702 can determine suitable SSC codes and/orscrambling codes to reduce interference of transmitted synchronizationinformation. Specifically, various mechanisms for generating andscrambling SSCs, generating scrambling codes (e.g., based on threelength-31 M-sequences) for such SSCs, and selecting sequence indicesbased on characteristics of such SSCs can be accomplished by basestation 702. Accordingly, system 700 facilitates improved mobilecommunication by providing improved transmission characteristics for OTAmessages received at one or more mobile devices 704 in a mobilecommunication environment.

System 700 comprises a base station 702 (e.g., access point, . . . )with a receiver 710 that receives signal(s) from one or more mobiledevices 704 through a plurality of receive antennas 706, and atransmitter 728 that transmits to the one or more mobile devices 704through a transmit antenna(s) 708. Receiver 710 can receive informationfrom receive antennas 706 and can further comprise a signal recipient(not shown) that receives uplink data synchronized in accordance with aPSC and/or SSC provided by base station 702. Additionally, receiver 710is operatively associated with a demodulator 712 that demodulatesreceived information. Demodulated symbols are analyzed by a processor714 that is coupled to a memory 716 that stores information related togenerating a sequence matrix to provide synchronization and/orscrambling codes, as well as selecting, scrambling and/or multiplexingsuch sequences to form the SSCs, selecting sequences according to an SSCcodebook as described herein, known in the art or made known to one ofskill in the art by way of the context provided herein, and/or any othersuitable information related to performing the various actions andfunctions set forth herein.

Processor 714 is further coupled to a logic processor 718 that cangenerate a sequence matrix from at least a base M-sequence and cyclicshifted variations of such sequence (e.g., n cyclic shifted variations).The processor 714 can be further coupled to a data transformation module720 that can scramble various sequences of the sequence matrix providedby the logic processor 718. For instance, the data transformation module720 can employ a common binary scrambling code based on a PSC associatedwith a wireless communication to scramble at least one such sequencepertinent to an SSC, as described herein.

Additionally, the processor 714 can be coupled to a multiplexing module722 that can generate an SSC based on at least one scrambled sequenceprovided by the data transformation module 720. For instance, where thedata transformation module 720 scrambles a base sequence of a sequencematrix, any suitable cyclic shifted variation of the scrambled basesequence, and/or the scrambled base sequence itself, can be utilized bythe multiplexing module 722 to form the SSC. The SSC can be formed byinterleaving two or more sequences, repetition of one or more sequences,addition/truncation of bits, or the like, as required.

Processor 714 can further be associated with a sequence module 724.Sequence module 724 can generate the scrambling code from one or moresequences provided by the logic processor 718 (e.g., based on a commonpolynomial expression that is different from an expression used togenerate SSC-related sequences). In one example, the sequence module 724can generate three suitable M-sequences, either length-63 or length-31,to form the scrambling code(s). The three M-sequences can be generatedfrom a base M-sequence and cyclic shifted variations of the baseM-sequence, for example. Further, in at least some aspects, at least 20cyclic shifted variations of the base M-sequence can be created, and thethree M-sequences can comprise the base M-sequence, a tenth cyclicshifted variation, and a twentieth cyclic-shifted variation. It shouldbe appreciated, however, that other variations of the base sequence canbe employed, and other selected members of the set of variations can beutilized for the three (or, e.g., other suitable number) of scramblingcode sequences.

Base station 702 can further comprise a modulator 726 that can map anSSC to an OTA message transmitted by transmitter 728. In one aspect, theSSC can be mapped onto some or all sub-carrier channels of an OFDMtransmission. The OTA message can be sent via the transmission antennas708 to mobile device 704. It should be appreciated that base station 702can be part of a planned, semi-planned or unplanned deployment ofseveral base stations (not depicted) operating in a common area.Generation, scrambling and assignment of SSCs can be implemented by basestation 702 in a predetermined manner specified by logic processor 718,and sequence module 724, or other instructions stored in memory 716 andexecuted by processor 714 pertinent to multi-base station operation. Inthe alternative, base station 702 can communicate with other nearby basestations over a backhaul network (not depicted) to coordinate assignmentof SSCs to various base stations of a cell site. In at least one otheralternative, code assignments can be specified at least in part by acentralized entity (not depicted, but see FIG. 3, supra) and provided tobase station 702. Accordingly, system 700 can function as part of a RANcomprising multiple base stations.

FIG. 8 illustrates a block diagram of an example system 800 thatcomprises a mobile device 802. Mobile device 802 can be configured toreceive and decode synchronization information within an OTA messagetransmitted by a base station 804. Decoding processes at the mobiledevice 802 can be inverse to similar processes employed by the basestation 804. Instructions for receiving and decoding the message can bepre-loaded at the mobile device 802, included at least in part withinthe OTA message, obtained by way of a software/firmware patch (e.g.,over a network, or connection to a computing device), or a combinationthereof or of the like.

Mobile handset 802 includes at least one antenna 806 (e.g., atransmission receiver or group of such receivers comprising an inputinterface) that receives a signal (e.g., comprising synchronizationinformation pertinent to facilitating remote wireless communication) anda receiver 808, which performs typical actions (e.g., filters,amplifies, down-converts, etc.) on the received signal. Specifically,antenna 806 and transmitter 830 (collectively referred to as atransceiver) can be configured to facilitate wireless data exchange withbase station 804.

Antenna 806 and receiver 808 can also be coupled with a demodulator 810that can demodulate received symbols and provide them to a processor 812for evaluation. Specifically, demodulator 810 can extract at leastsynchronization information from received wireless transmissions. Forfrequency-based transmission, for instance, the demodulator 810 canextract the synchronization information from sub-carrier frequencies ofthe wireless transmissions. In one aspect, the synchronizationinformation can comprise at least an SSC further comprised of at leasttwo sequences scrambled with a common PSC-based binary scrambling code.A signal processor 814 can employ a common PSC-based binary descramblingcode to decipher the at least two sequences comprising the received SSC.The descrambling code can be substantially equivalent to the scramblingcode employed by the base station 804, or can be a counterpart thereof(e.g., an inverted scrambling code). In at least one aspect, decodingthe synchronization information involves a data processor 820 thatapplies a first reverse cyclic shift to a first of the two sequencesassociated with the SSC and a second reverse cyclic shift to a second ofthe two sequences. In such aspect(s), the signal processor 814 can thenapply the descrambling code to the shifted first sequence and shiftedsecond sequence to decipher the SSC.

Once the received SSC is decoded, a logic processor 818 can extractidentification information pertinent to a device (804) that transmittedthe received data. Such information can be utilized to further decodereceived data (e.g., payload information) and/or facilitatecommunication with the transmitting device (804).

It should be appreciated that processor 812 can control and/or referenceone or more components (806, 808, 810, 816, 822) of the mobile handset802. Further, processor 812 can execute one or more modules,applications, engines, or the like (814, 818, 820) that compriseinformation or controls pertinent to executing functions of the mobiledevice 802. For instance, such functions can include receiving data froma remote source (804), decoding the received data based on a particulardescrambling code, identifying a mobile network transmitter (804)associated with the deciphered code, or the like, as described above.

Mobile handset 802 can additionally include memory 816 that isoperatively coupled to processor 812. Memory 816 can store data to betransmitted, received, and the like. Further, memory 816 can store themodules, applications, engines, etc. (814, 818, 820) executed byprocessor 812, above.

Mobile handset 802 can still further comprise a modulator 822, and atransmitter 824 that transmits generated signals (e.g., by processor 812and modulator 822) to, for instance, base station 804, an access point,another access terminal, a remote agent, etc. As described, system 800provides a mobile device 802 that can facilitate receiving codedsynchronization information provided by a base station 804 and decipherthe coded information to facilitate wireless communication between suchdevices (802, 804). Because the synchronization information can beencoded based on a selected SSC codebook and/or based on certainscrambling codes, reduced interference and improved reliability andreduced power consumption at the mobile device 802 can potentially beaccomplished.

The aforementioned systems have been described with respect tointeraction between several components, modules and/or communicationinterfaces. It should be appreciated that such systems andcomponents/modules/interfaces can include those components orsub-components specified therein, some of the specified components orsub-components, and/or additional components. For example, a systemcould include SSC generator 108, pruning module 510 and transmissionprocessor 512, or a different combination of these and other components.Sub-components could also be implemented as components communicativelycoupled to other components rather than included within parentcomponents. Additionally, it should be noted that one or more componentscould be combined into a single component providing aggregatefunctionality. For instance, signal simulation module 608 can includesignal correlation module 610, or vice versa, to facilitate determiningpeak to average power and cross correlation of an SSC by way of a singlecomponent. The components may also interact with one or more othercomponents not specifically described herein but known by those of skillin the art.

Furthermore, as will be appreciated, various portions of the disclosedsystems above and methods below may include or consist of artificialintelligence or knowledge or rule based components, sub-components,processes, means, methodologies, or mechanisms (e.g., support vectormachines, neural networks, expert systems, Bayesian belief networks,fuzzy logic, data fusion engines, classifiers . . . ). Such components,inter alia, and in addition to that already described herein, canautomate certain mechanisms or processes performed thereby to makeportions of the systems and methods more adaptive as well as efficientand intelligent.

In view of the exemplary systems described supra, methodologies that maybe implemented in accordance with the disclosed subject matter will bebetter appreciated with reference to the flow charts of FIGS. 9-11.While for purposes of simplicity of explanation, the methodologies areshown and described as a series of blocks, it is to be understood andappreciated that the claimed subject matter is not limited by the orderof the blocks, as some blocks may occur in different orders and/orconcurrently with other blocks from what is depicted and describedherein. Moreover, not all illustrated blocks may be required toimplement the methodologies described hereinafter. Additionally, itshould be further appreciated that the methodologies disclosedhereinafter and throughout this specification are capable of beingstored on an article of manufacture to facilitate transporting andtransferring such methodologies to computers. The term article ofmanufacture, as used, is intended to encompass a computer programaccessible from any computer-readable device, device in conjunction witha carrier, or storage medium.

FIG. 9 depicts a flowchart of an example methodology 900 for reducinginterference of multiple SSC transmissions according to aspects of thesubject disclosure. Method 900, at 902, can generate a sequence matrix.The sequence matrix can comprise M-sequences generated from one or morepolynomial expressions. In at least one aspect of the subjectdisclosure, the M-sequences are generated from a polynomial expressionof the form x^5+x^2+1 over GF(2). Additionally, the M-sequences cancomprise a base sequence and various variations of the base sequence,such as provided by cyclic shifting the base sequence.

At 904, method 900 can scramble at least one M-sequence with a PSC-basedscrambling code associated with a wireless communication. The scramblingcode can be generated, for instance, based on sequences identified byindices associated with the PSC. In one aspect, the at least oneM-sequence scrambled with the scrambling code can comprise a pair ofsequences that are multiplexed to form an SSC. The pair of M-sequencescan be scrambled prior to or after such multiplexing. In another aspect,the base M-sequence of the above sequence matrix can be the at least oneM-sequence scrambled at reference number 904, such that each variationof the scrambled base M-sequence is also scrambled. Accordingly, thesequence matrix comprises scrambled sequences according to such aspect.

At 906, method 900 can generate an SSC based on the scrambledM-sequence. As indicated above, the SSC can be generated by multiplexingmultiple sequences (e.g., sequence pairs, sequence triplets), truncatingone or more bits of such sequences, repeating one or more bits of suchsequences, or a combination thereof or of the like, as required togenerate an SSC of a desired length (e.g., length-62). At 908, method900 can map the SSC onto sub-components of an OTA message (e.g.,sub-carrier channels of an OFDM transmission).

An SSC scrambled with a PSC-based scrambling code, generated by method900, can provide improved interference characteristics for wirelesscommunication. It should be appreciated that the scrambling code can begenerated from the same polynomial utilized to generate the SSC, or apolynomial different than that utilized to generate the SSC. In at leastone aspect, the polynomial utilized to generate the scrambling code isof the form 1+x^2+x^3+x^4+x^5. Further, such polynomial can be utilizedto generate a base scrambling sequence. Cyclic shifted variations of thebase scrambling sequence can be generated to provide a scramblingsequence matrix. In one specific aspect of the subject disclosure,twenty or more cyclic shifted variations of the scrambling sequence aregenerated and combined with the base scrambling sequence to form thescrambling sequence matrix. According to such aspects, the scramblingcode can be generated from substantially three sequences of thescrambling sequence matrix. As an example, the base scrambling sequence,a tenth cyclic shifted variation of the base scrambling sequence, and atwentieth cyclic shifted variation of the base scrambling sequence canbe utilized to generate the PSC-based scrambling code.

FIG. 10 depicts a flowchart of a sample methodology 1000 for scramblingOTA SSC transmission according to one or more aspects. Method 1000, at1002, can generate a sequence matrix as described herein. At 1004,method 1000 can select two sequences from the matrix to generate an SSC.The sequences can be selected based on characteristics of an SSC coderesulting from the selected sequences. According to one specificexample, the characteristics can comprise a PAPR of the SSC code, across-correlation factor of the SSC code, or a suitable combinationthereof.

At 1006, method 1000 can determine whether the sequences are firstscrambled or multiplexed. Such determination can be based on projectedinterference characteristics of resulting SSC codes, optionally inconjunction with prevailing wireless transmission characteristics of aRAN (e.g., multi-path scattering, signal reflection/refraction, or thelike, as known in the art of radio frequency propagation and/or mobilecommunication technology). If the sequences are first multiplexed,method 1000 can proceed to 1014, if the sequences are first scrambled,method 1000 can proceed to 1008.

At 1008, method 1000 can generate a PSC-based scrambling code from asequence matrix generated from one or more polynomial expressions, asdescribed herein (e.g., see methodology 900, supra). At 1010, the twosequences selected from the sequence matrix can be scrambled utilizingthe PSC-based scrambling code. At 1012, the sequences can then beinterleaved to form an SSC. The SSC can be mapped to an OTA message andtransmitted in conjunction with one or more wireless communications.

At 1014, method 1000 can interleave the two sequences selected from thesequence matrix to form a full-length sequence. At 1016, a full-lengthscrambling code can be generated as described herein. At 1018, thefull-length sequence can be scrambled by employing the scrambling codegenerated at reference number 1016. Finally, at 1018, an SSC can begenerated from the scrambled interleaved sequences, which can be mappedto the OTA message discussed above.

FIG. 11 illustrates a flowchart of a sample methodology 1100 forgenerating scrambled SSCs according to at least one aspect. At 1102,method 1100 can generate an M-sequence from a polynomial expression. Thepolynomial expression can, in some instances, have the form x^5+x^2+1over GF(2). At 1104, method 1100 can scramble the M-sequence with aPSC-based scrambling code. The PSC-based scrambling code can begenerated from one or more scrambling sequences obtained from one ormore scrambling polynomial expressions. According to at least oneaspect, the scrambling polynomial expressions can comprise a singleexpression of the form 1+x^2+x^3+x^4+x^5.

At 1106, the scrambled M-sequence is cyclic shifted n times to create ndistinct scrambled variations of the scrambled M-sequence. The scrambledM-sequence and n distinct scrambled variations can be compiled into ascrambled sequence matrix. At 1108, two of the scrambled sequences ofthe scrambled sequence matrix are selected to form an SSC. The selectedsequences can be multiplexed to form a full-length scrambled sequence,as described herein. It should be appreciated that the two selectedsequences can be based on underlying characteristics of an SSC derivedfrom the sequences. In one aspect, the underlying characteristiccomprises a PAPR of the SSC as compared with a PAPR threshold. Inanother aspect, the underlying characteristic comprises across-correlation factor as compared with a correlation threshold. Inyet another aspect, the underlying characteristic comprises a suitablecombination of the foregoing.

In at least one further aspect, the two selected sequences can be basedon a predetermined number of desired SSCs. As a particular example,where the scrambled sequence matrix comprises 31 scrambled sequences oflength substantially one half the length of a desired SSC code, 170 or340 sequence pairs can be selected, based on the PAPR and/orcross-correlation characteristics, discussed above. Selection of SSCsequence pairs in such a manner can provide reduced interference fortransmitted synchronization information, potentially reducing powerconsumption of receiving devices and improving overall communicationquality in a mobile communication environment. Accordingly, method 1100can provide a significant benefit for various mobile communicationtechnologies, as described herein.

FIG. 12 depicts a block diagram of an example system 1200 that canfacilitate wireless communication according to some aspects disclosedherein. On a downlink, at access point 1205, a transmit (TX) dataprocessor 1210 receives, formats, codes, interleaves, and modulates (orsymbol maps) traffic data and provides modulation symbols (“datasymbols”). A symbol modulator 1215 receives and processes the datasymbols and pilot symbols and provides a stream of symbols. A symbolmodulator 1220 multiplexes data and pilot symbols and provides them to atransmitter unit (TMTR) 1220. Each transmit symbol can be a data symbol,a pilot symbol, or a signal value of zero. The pilot symbols can be sentcontinuously in each symbol period. The pilot symbols can be frequencydivision multiplexed (FDM), orthogonal frequency division multiplexed(OFDM), time division multiplexed (TDM), code division multiplexed(CDM), or a suitable combination thereof.

TMTR 1220 receives and converts the stream of symbols into one or moreanalog signals and further conditions (e.g., amplifies, filters, andfrequency upconverts) the analog signals to generate a downlink signalsuitable for transmission over the wireless channel. The downlink signalis then transmitted through an antenna 1225 to the terminals. Atterminal 1230, an antenna 1235 receives the downlink signal and providesa received signal to a receiver unit (RCVR) 1240. Receiver unit 1240conditions (e.g., filters, amplifies, and frequency downconverts) thereceived signal and digitizes the conditioned signal to obtain samples.A symbol demodulator 1245 demodulates and provides received pilotsymbols to a processor 1250 for channel estimation. Symbol demodulator1245 further receives a frequency response estimate for the downlinkfrom processor 1250, performs data demodulation on the received datasymbols to obtain data symbol estimates (which are estimates of thetransmitted data symbols), and provides the data symbol estimates to anRX data processor 1255, which demodulates (i.e., symbol demaps),deinterleaves, and decodes the data symbol estimates to recover thetransmitted traffic data. The processing by symbol demodulator 1245 andRX data processor 1255 is complementary to the processing by symbolmodulator 1215 and TX data processor 1210, respectively, at access point1205.

On the uplink, a TX data processor 1260 processes traffic data andprovides data symbols. A symbol modulator 1265 receives and multiplexesthe data symbols with pilot symbols, performs modulation, and provides astream of symbols. A transmitter unit 1270 then receives and processesthe stream of symbols to generate an uplink signal, which is transmittedby the antenna 1235 to the access point 1205. Specifically, the uplinksignal can be in accordance with SC-FDMA requirements and can includefrequency hopping mechanisms as described herein.

At access point 1205, the uplink signal from terminal 1230 is receivedby the antenna 1225 and processed by a receiver unit 1275 to obtainsamples. A symbol demodulator 1280 then processes the samples andprovides received pilot symbols and data symbol estimates for theuplink. An RX data processor 1285 processes the data symbol estimates torecover the traffic data transmitted by terminal 1230. A processor 1290performs channel estimation for each active terminal transmitting on theuplink. Multiple terminals can transmit pilot concurrently on the uplinkon their respective assigned sets of pilot subbands, where the pilotsubband sets can be interlaced.

Processors 1290 and 1250 direct (e.g., control, coordinate, manage,etc.) operation at access point 1205 and terminal 1230, respectively.Respective processors 1290 and 1250 can be associated with memory units(not shown) that store program codes and data. Processors 1290 and 1250can also perform computations to derive frequency and impulse responseestimates for the uplink and downlink, respectively.

For a multiple-access system (e.g., SC-FDMA, FDMA, OFDMA, CDMA, TDMA,etc.), multiple terminals can transmit concurrently on the uplink. Forsuch a system, the pilot subbands can be shared among differentterminals. The channel estimation techniques can be used in cases wherethe pilot subbands for each terminal span the entire operating band(possibly except for the band edges). Such a pilot subband structurewould be desirable to obtain frequency diversity for each terminal. Thetechniques described herein can be implemented by various means. Forexample, these techniques can be implemented in hardware, software, or acombination thereof. For a hardware implementation, which can bedigital, analog, or both digital and analog, the processing units usedfor channel estimation can be implemented within one or more applicationspecific integrated circuits (ASICs), digital signal processors (DSPs),digital signal processing devices (DSPDs), programmable logic devices(PLDs), field programmable gate arrays (FPGAs), processors, controllers,micro-controllers, microprocessors, other electronic units designed toperform the functions described herein, or a combination thereof. Withsoftware, implementation can be through modules (e.g., procedures,functions, and so on) that perform the functions described herein. Thesoftware codes can be stored in memory unit and executed by theprocessors 1290 and 1250.

FIGS. 13, 14, and 15 provide block diagrams of example systems 1300,1400, 1500 for implementing various aspects of the subject disclosure.System 1300 can comprise a module 1302 for generating a sequence matrixfrom a base M-sequence and cyclic shifted variations of the baseM-sequence. The base M-sequence can be generated from a polynomialexpression, as described herein. Bits of each cyclic shifted variationof the base sequence can be either single shifted, double shifted bits,triple shifted bits, etc., or a suitable combination thereof. The basesequence and the shifted variations can be utilized by the module 1302to form the sequence matrix.

System 1300 can also include a module 1304 for scrambling one or more ofthe M-sequences. The module 1304 can employ a scrambling code, such as aPSC-based scrambling code to scramble the M-sequences. The scramblingcode can be generated by creating a base scrambling sequence from apolynomial expression (e.g., different from that used to generate thesequence matrix), as described herein. Cyclic shifted variations of thebase scrambling sequence can be generated, and one or more of the basescrambling sequence and shifted variations can be utilized to generatethe scrambling code.

A module 1306 for generating an SSC can create the SSC utilizing atleast one scrambled M-sequence. For instance, the scrambledM-sequence(s) can be interleaved, truncated, repeated, or a combinationthereof or of the like, as suitable depending on a length of the atleast one scrambled M-sequence compared with a desired length of theSSC. System 1300 can further comprise a module 1308 for mapping the SSConto an OTA transmission. For instance, bits of the SSC can be mapped tosub-carrier channels of an OFDM transmission, code sub-divisions of aCDMA transmission, time sub-divisions of a TDMA transmission, orsuitable combinations of integrated systems. As described, system 1300can generate scrambled SSC codes exhibiting reduced interference in amobile communication environment.

System 1400 can comprise a module 1402 for forming a sequence matrixfrom a base M-sequence and n cyclic shifted variations of the baseM-sequence, as described herein. Further, system 1400 can comprise amodule 1404 for indexing sequence pairs of the sequence matrix. Themodule can generate at least (n+1)^2 indices for each distinct sequencepair of the sequence matrix. Furthermore, system 1400 can comprise amodule 1406 for determining PAPR and/or correlation of SSC codesresulting from sequence pairs. The module 1406 can select apredetermined number of sequence pairs (e.g., substantially 170 sequencepairs, substantially 340 sequence pairs, or other suitable number basedat least in part on a number of base stations in a mobile site etc.)meeting PAPR and/or cross-correlation thresholds (e.g., below a desiredPAPR and/or below a desired correlation factor). Accordingly, SSCsresulting from the selected sequence pairs can have desired transmissioncharacteristics resulting in improved wireless transmission.

System 1500 can comprise a module 1502 for receiving wirelesstransmissions. The module 1502 can receive one or more wireless OTAtransmissions from a mobile network transmitter (e.g., base station(s)).The module 1502 can comprise one or more wireless antenna's (e.g., radioantenna), a receiver for pre-conditioning received signals, or the like.System 1500 can further comprise a module 1504 for extracting an SSCfrom transmissions received by module 1502. Extraction can be based onsignal demodulation, conditioning, and the like, as known in the art. Amodule 1506 for descrambling the SSC can employ a common PSC-basedbinary descrambling code to decipher the SSC. In one aspect, thedescrambling code can be substantially similar to a scrambling code usedto scramble the SSC, or a variation (e.g., by inverting the bits of thescrambling code) of such scrambling code. Additionally, system 1500 cancomprise a module 1508 for determining an identity of the mobile networktransmitter from the deciphered SSC. For instance, a transmitter IDencoded into the SSC can be read and cross-referenced with an ID storedin memory. The transmitter ID can be utilized, for instance, tofacilitate wireless communication between a mobile device and the mobilenetwork transmitter. Where received signals exhibit reducedinterference, system 1500 can provide reduced power consumption andimproved communication reliability in a mobile communicationenvironment.

What is claimed is:
 1. A user equipment configured to mitigatesynchronization code interference in a wireless communication system,comprising: a processor configured to: receive, at a user equipment, asignal comprising synchronization information from a base station; andextract the synchronization information, wherein: the synchronizationinformation includes a secondary synchronization code (SSC), the SSCcomprises a scrambled pair of sequences combined via interleaving, thescrambled pair of sequences comprises a pair of sequences scrambledusing generated scrambling codes, and the generated scrambling codescomprise at least a primary synchronization code (PSC)-based scramblingcode; and a memory coupled to the processor.
 2. The user equipment ofclaim 1, wherein the pair of sequences comprise cyclic shiftedvariations of a base sequence.
 3. The user equipment of claim 1, whereinthe pair of sequences is selected based on at least one projectedinterference characteristic of the SSC.
 4. The user equipment of claim1, wherein the PSC-based scrambling code is generated based on sequencesthat are identified by indices associated with the PSC.
 5. The userequipment of claim 1, wherein the PSC-based scrambling code is based ona cyclic shift of a base sequence.
 6. The user equipment of claim 1,wherein the SSC is mapped to an over-the-air message.
 7. The userequipment of claim 1, wherein the processor is further configured todecipher the scrambled pair of sequences using a common PSC-based binarydescrambling code.
 8. A method for mitigating synchronization codeinterference in a wireless communication system, comprising: receiving,at a user equipment, a signal comprising synchronization informationfrom a base station; and extracting the synchronization information,wherein: the synchronization information includes a secondarysynchronization code (SSC), the SSC comprises a scrambled pair ofsequences combined via interleaving, the scrambled pair of sequencescomprises a pair of sequences scrambled using generated scramblingcodes, and the generated scrambling codes comprise at least a primarysynchronization code (PSC)-based scrambling code.
 9. The method of claim8, wherein the pair of sequences comprise cyclic shifted variations of abase sequence.
 10. The method of claim 8, wherein the pair of sequencesis selected based on at least one projected interference characteristicof the SSC.
 11. The method of claim 8, wherein the PSC-based scramblingcode is generated based on sequences that are identified by indicesassociated with the PSC.
 12. The method of claim 8, wherein thePSC-based scrambling code is based on a cyclic shift of a base sequence.13. The method of claim 8, wherein the SSC is mapped to an over-the-airmessage.
 14. The method of claim 8, further comprising deciphering thescrambled pair of sequences using a common PSC-based binary descramblingcode.
 15. A user equipment configured to mitigate synchronization codeinterference in a wireless communication system, comprising: means forreceiving, at a user equipment, a signal comprising synchronizationinformation from a base station; and means for extracting thesynchronization information, wherein: the synchronization informationincludes a secondary synchronization code (SSC), the SSC comprises ascrambled pair of sequences combined via interleaving, the scrambledpair of sequences comprises a pair of sequences scrambled usinggenerated scrambling codes, and the generated scrambling codes compriseat least a primary synchronization code (PSC)-based scrambling code. 16.The user equipment of claim 15, wherein the pair of sequences comprisecyclic shifted variations of a base sequence.
 17. The user equipment ofclaim 15, wherein the pair of sequences is selected based on at leastone projected interference characteristic of the SSC.
 18. The userequipment of claim 15, wherein the PSC-based scrambling code isgenerated based on sequences that are identified by indices associatedwith the PSC.
 19. The user equipment of claim 15, wherein the PSC-basedscrambling code is based on a cyclic shift of a base sequence.
 20. Theuser equipment of claim 15, wherein the SSC is mapped to an over-the-airmessage.
 21. The user equipment of claim 15, further comprising meansfor deciphering the scrambled pair of sequences using a common PSC-basedbinary descrambling code.
 22. A non-transitory computer-readable mediumcomprising computer-readable instructions configured to mitigatesynchronization code interference in a wireless communication system,the instructions executable by at least one computer to: receive, at auser equipment, a signal comprising synchronization information from abase station; and extract the synchronization information, wherein: thesynchronization information includes a secondary synchronization code(SSC), the SSC comprises a scrambled pair of sequences combined viainterleaving, the scrambled pair of sequences comprises a pair ofsequences scrambled using generated scrambling codes, and the generatedscrambling codes comprise at least a primary synchronization code(PSC)-based scrambling code.
 23. The non-transitory computer-readablemedium of claim 22, wherein the pair of sequences comprise cyclicshifted variations of a base sequence.
 24. The non-transitorycomputer-readable medium of claim 22, wherein the pair of sequences isselected based on at least one projected interference characteristic ofthe SSC.
 25. The non-transitory computer-readable medium of claim 22,wherein the PSC-based scrambling code is generated based on sequencesthat are identified by indices associated with the PSC.
 26. Thenon-transitory computer-readable medium of claim 22, wherein thePSC-based scrambling code is based on a cyclic shift of a base sequence.27. The non-transitory computer-readable medium of claim 22, wherein theSSC is mapped to an over-the-air message.
 28. The non-transitorycomputer-readable medium of claim 22, wherein the instructions arefurther executable by at least one computer to decipher the scrambledpair of sequences using a common PSC-based binary descrambling code.